Circuit breaker operating means



Feb. 17, 1948. R. R. BUSH CIRCUIT BREAKER OPERATING MEANS Filed Aug. 30,1945 44 mil n:

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hwven tor: Ralph RBush,

H i s Atfiorm ey.

Patented Feb. 17, 1948 CIRCUIT BREAKER OPERATING MEANS Ralph R. Bush,Upper Darby, Pa., assignor to General Electric Company, a corporation ofNew York Application August 30, 1945, Serial No. 613,505

Claims. 1

My invention relates to switches and electric circuit breakers, and moreparticularly to operating means for electric circuit breakers.

Electric circuit breakers and switches are usually provided withsuitable means for opening and closing the same. In many types ofcircuit breakers it is common practice to provide a solenoid operatedmechanism for closing the breaker. During the closing operation suitableopening springs are charged and the breaker is latched closed with thelatch holding the opening springs in charged condition in readiness forhigh speed opening of the circuit breaker. Sometimes such circuitbreakers or switches are closed when a very abnormal current conditionexists on the circuit controlled thereby. Such an abnormal currentcondition might be a short circuit and under such conditions it isdesired to open the circuit breaker at high speed. It is obvious thatwhen such a circuit breaker is closed on a short circuit an arc will bedrawn before the contacts are completely closed and before the openingsprings arecompletely charged. Consequently the opening springs, whichare not completely charged, produce a weak opening action with aresultant unsatisfactory opening operation. It would be desirable toprovide some supplementary or auxiliary means to speed the opening ofthe circuit breaker under such conditions.

It is an object of my invention to provide a new and improved operatingmeans for electric circuit breakers and switches.

It is another object of my invention to provide a supplementary openingmeans for circuit breakers which supplementary opening means is simpleand compact and which is instantly operative to open the circuit breakerunder abnormal conditions of the circuit when the normal means foropening the circuit breaker are inadequate.

Further objects and advantages of my invention will become apparent asthe following description proceeds and the features of novelty whichcharacterize my invention will be pointed out with particularity in theclaims annexed to and forming a part of this specification.

For a better understanding of my invention reference may be had to theaccompanying drawing in which Fig. 1 is a schematic diagram of a portionof an electric circuit interrupter embodying my invention, and Fig. 2 isan enlarged sectional View of a portion of the operating mechanism shownin Fig. 1.

Although my invention may be applicable to any sort of electric switchor circuit breaker, it is particularly applicable to electric switchesor circuit breakers employing the operating mechanism disclosed andclaimed in United States Letters Patent 1,988,287, Thumim. and copendingapplication Serial No. 567,468, Baskerville, filed December 9, 1944,both assigned to the same assignee as the present application.

Referring now to Fig. 1, there is illustrated a portion of an electriccircuit breaker embodying my invention. This circuit breaker isdesignated by the numeral l and comprises a pair of relatively movablecontacts 2 and 3. The contact 3 is a movable contact and is supported onan arm 4 rotatable about a pivot 5. Contacts 2 and 3 are connectedthrough suitable insulated conductor studs 6 and 1 to an electric powerline 8 adapted.

to be controlled thereby. Such a circuit breaker is usually a polyphasebreaker but to simplify the drawing only a single phase thereof isshown.

In order to cause relative movement between the contacts 2 and 3 movablecontact supporting arm l is connected through a suitable operating rod9, a crank Ill pivotally mounted at H, and a suitable link l2 with acollapsible thrust transmitting linkage generally indicated at I 3 andmounted in a housing 14 closely associated with the housing of circuitbreaker I.

Any suitable motive means for operating mechanism I3 may be providedsuch for example as a fluid motor, electric motor, solenoid, or thelike. As illustrated in Fig. l, the motive means generally indicated atI5 is mounted below operating mechanism l3. This motive means actuates aplunger I6 which is arranged for vertical movement. The thrusttransmitting linkage I3 which provides a trip free mechanism comprises.

an operating crank l1 pivotally mounted at l8. One end of operatingcrank I! is pivotally connected as at [9 to link I 2. The other end ofoperating crank I! is connected by pivotal means as indicated at 22 to acollapsible or floating linkage which is very similar to that disclosedand claimed in Thumim Patent 1,827,626, granted October 13, 1931, andassigned to the same assignee as the present application.

This floating 0r collapsible linkage comprises a link 2| and a link 22pivotally related by a shaft having an extension 23. The free end oflink 22 is pivotally connected, as indicated at 24, with a crank orlever 25 rotatable about a fixed pivot 25. It will be observed from thedrawing that links 2| and 22 form a toggle with the shaft having theextension 23 comprising the knee joint thereof. The plunger [6 isadapted in its upward movement to engage a roller 2! positioned at theknee of the toggle and upward movement of plunger l6 straightens thetoggle comprising links 2| and 22 and causes rotation of operating crankll in a counter-clockwise direction about pivot H3. The limitingmovement of the toggle comprising links 2| and 22 is determined by anextension 28 on link 2| which cooperates with a pin 29 on link 22 in amanner which is clearly obvious from Fig. 1.

Rotatable about the axis of pivot 24 between link 22 and crank 25 istrip latch roller 30 which is adapted to rest on a stop bolt 3|supported from the base 32 of housing it. A suitable resetting spring 33tends to rotate crank or lever 25 in a counter-clockwise direction sothat trip latch roller 33 tends to be in engagement with stop 3|. Itwill be obvious that if trip latch roller 30 is maintained in a fixedposition against stop bolt 3| a force applied to toggle roller 21 willcause rotation of crank l7 about pivot l8. If, however, trip latchroller 30 is free to move away from stop bolt 3| then the thrusttransmitting linkage collapses toward the right and rotation ofoperatingcrank i7 will not occur for the toggle links 2| and 22straighten and cause crank 25 to rotate clockwise against the bias ofits resetting spring 33.

In order to hold trip latch roller 3|] against stop bolt 3| thereby tocontrol the collapsible linkage, there is provided a trip latch 34pivotally mounted at 35. A trip latch spring as biases trip latch 3:3 tothe position indicated in Fig. 1 against stop 31. In this position triplatch 34 holds trip latch roller 39 in a fixed position against stopbolt 3|. A suitable trip coil 38 positioned in the manner disclosed andclaimed in Thumim Patent 1,988,287 referred to above is provided. Whenplunger 39 associated with trip coil 38 is moved to the left as viewedin Fig. 1 trip latch 34 is rotated so that trip latch roller 30 is freeto move with lever or crank 25 about pivot 26 causing collapse of thecollapsible thrust transmitting linkage l3.

In order to restrain the collapsible linkage in the thrust transmittingbreaker-closed position indicated in Fig. l, a pivotally mounted prop 40is provided rotatable about a shaft 4|. A suitable spring 42 biases prop40 in a clockwise direction against a stop 43. When the collapsiblelinkage is moved by the plunger It to the position indicated in Fig. 1,the prop 40 moves under the extension 23 of the shaft forming the kneeof the toggle comprising links 2| and 22 to hold the linkage in thethrust-transmitting position even though plunger l6 returns to theposition indicated in Fig. 1.

In order to cause high speed opening of the circuit breaker I there areprovided suitable circuit breaker opening springs such for example asthe spring 44. The energy stored in spring 44 is adapted to betransmitted through an operating rod 45 to crank I8. Spring 44 isadapted to be charged during the closing operation of the circuitbreaker so as to be in readiness to cause high speed opening of thecircuit breaker in the event that trip coil 38 is energized eitherautomatically in response to an overload condition, or manually whenopening of the breaker is initiated manually.

In the event that circuit breaker is closed when an abnormal currentcondition such as a severe short circuit exists on power line 8, tripcoil 38 will be energized to cause opening of the breaker before openingspring 44 is completely charged. High speed opening of circuit breakeris desired particularly under such conditions when spring 44 isincapable of causing such opening, namely, when opening is initiatedprior to complete charging of spring 44. To insure satisfactory openingoperation under such conditions there is provided in accordance with myinvention supplementary opening means generally indicated at 6. Suchsupplementary opening means may comprise any suitable high speed motivemeans. I have chosen to illustrate the motive means for supplementingthe opening spring 44 under abnormal conditions as comprising agunpowder mechanism including a cylinder 47 and a piston 48 reciprocallymounted in cylinder 47. Adjacent one end of cylinder 47 is a slidingbreech 49 wherein a suitable cartridge 55 may be inserted. The gunpowderbooster mechanism is schematically illustrated in the drawing and itmight well comprise a gunpowder mechanism of the type disclosed andclaimed in copending Bush et a1. application Serial No. 613,504, filedconcurrently with the present application and assigned to the sameassignee as the present invention. The cartridge 5% preferably containsa slow-burning smokeless powder with suitable means for igniting thepowder. Also included in the gunpowder mechanism 46 is a suitable firingpin 5i which is biased into the firing position by means of a spring Asuitable latch 53 biased into the latching position by gravity orsuitable spring means normally holds firing pin 5| in readiness to firecartridge Suitable manual meansSd may be provided to reset the firingpin after operation thereof.

It is desirable that suitable means be provided to initiate operation ofthe supplemental opening means 43 when it is needed. In order to actuatefiring pin iii in response to an excessive fault condition so that highspeed opening of circuit breaker l is caused under such conditions, atrip coil 55 is provided having a plunger 56 for engaging latch 53. Tripcoil 55 is connected to a source of suitable control potential throughcontacts 57 which are adapted to be controlled by a normally open switch58 associated-with an electro-responsive device 59. The winding ofelectro-responsive device 59 is connected to the secondary winding 59 ofa suitable current gized sufficiently to cause switch 58 to bridgewhereupon trip coil 55 actuates contacts 51 plunger 5% to release firingpin latch 53 with the consequent firing of cartridge '50 and actuationof plunger 48.

As illustrated in Fig. 1, the cylinder 41 is preferably pivotallymounted as indicatedat 5| to housing I4 and the piston 48 is pivotallyconnected as indicated at B2 to a crank 63 pivotally mounted on pivot 35for trip latch 34. Crank 63 is provided with an arm 64 which engages apin 65 on trip latch 34. Initial movement of piston 48 causescounter-clockwise rotation of trip latch 34 by virtue of the fact-thatarm 64 of crank 63 rotates to brush trip latch 34 out of its restrainingposition with reference to roller 38. Continued downward movement ofpiston 38 furthermore causes arm 66 of crank 63 to engage trip latchroller 39 and positively push it in a direction to cause high speedopening of circuit breaker In view of the detailed'descrjiption includedabove the operation of the operating means of my invention will beobvious to those skilled in the art. In the event of an abnormal currentcondition particularly when it is possible that the normal opening meansmay not be capable of satisfactorily opening the circuit breaker,supplemental opening mechanism as is rendered effective to not onlyoperate trip latch 34 faster than it could be operated by trip coil 38,but furthermore to positively move the operating mechanism in a mannerto cause high speed opening of circuit breaker l,

Although the gunpowder mechanism which provides the supplemental openingmeans is illustrated as a single-shot device, it will be obvious that acartridge magazine could be employed in a manner such as is disclosed inRead Patent 723,183, assigned to the same assignee as the presentapplication.

While I have shown and described a particular embodiment of myinvention, it will be obvious to those skilled in the art that variouschanges and modifications may be made without departing from myinvention in its broader aspects and I, therefore, aim in the appendedclaims to cover all such changes and modifications as fall within thetrue spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In an operating mechanism for an electric circuit breaker, a forcetransmitting linkage, motive means for actuating said breaker to theclosed position through said linkage, energy storage means for openingsaid circuit breaker adapted to be charged by said motive means duringthe closing operation of said circuit breaker, means for latching saidcircuit breaker in the closed position and for holding said energystorage means in the charged condition, means for releasing saidlatching means to permit said energy storage means to open said circuitbreaker, a supplemental opening means for releasing said latching meansand then exerting an opening effect directly through said linkage, andmeans responsive to an abnormal current condition on the circuitassociated with said circuit breaker for actuating said supplementalopening means to cause high speed release of said latching means andopening of said circuit breaker.

2. In an operating mechanism for an electric circuit breaker, a forcetransmitting linkage, motive means for actuating said breaker to theclosed position through said linkage, energy storage means for openingsaid circuit breaker adapted to be charged by said motive means duringthe closing operation of said circuit breaker, means for latching saidcircuit breaker in the closed position and for holding said energystorage means in the charged condition, means for releasing saidlatching means to permit said energy storage means to open said circuitbreaker, a supplemental opening means comprising a gunpowder mechanism,and means responsive to an abnormal current condition on the circuitassociated with said circuit breaker for actuating said supplementalopening means to cause high speed release of said latching means andopening of said circuit breaker.

3. In an operating mechanism for an electric circuit breaker, a forcetransmitting linkage, motive means for actuating said breaker to theclosed position through said linkage, energy storage means for openingsaid circuit breaker adapted to be charged by said motive means duringthe closing operation of said circuit breaker,

means for latching said circuit breaker in the closed position and forholding said energy storage means in the charged condition, means forreleasing said latching means to permit said energy storage means toopen said circuit breaker, a supplemental opening means comprising agunpowder mechanism including a movable breech, a cartridg arranged tobe positioned in said breech, a plunger adapted to be actuated uponfiring of said cartridge, means responsive to an abnormal currentcondition on the circuit associated with said circuit breaker for firingsaid cartridge, and means responsive to movement of said plunger forreleasing said latching means at high speed and moving said circuitbreaker to the open position.

4. In an operating mechanism for an electric circuit breaker, a forcetransmitting linkage, motive means for actuating said breaker to theclosed position through said linkage, energy storage means for openingsaid circuit breaker adapted to be charged by said motive means duringthe closing operation of said circuit breaker, means for latching saidcircuit breaker in the closed position and for holding said energystorage means in the charged condition, means for releasing saidlatching means to permit said energy storage means to open said circuitbreaker, a supplemental opening means comprising a pivotally mountedgunpowder mechanism including a movable breech, a cartridge arranged tobe positioned in said breech, a plunger positioned so as to be actuatedupon firing of said cartridge, means responsive to an abnormal currentcondition on the circuit associated with said circuit breaker for firingcartridge, and means responsive to movement of said plunger forreleasing said latching means at high speed and moving said circuitbreaker to the open position.

5. In an operating mechanism for an electric circuit breaker, a forcetransmitting linkage, motive means for actuating said breaker to theclosed position through said linkage, energy storage means for openingsaid circuit breaker adapted to be charged by said motive means duringthe closing operation of said circuit breaker, means for latching saidcircuit breaker in the closed position and for holding said energystorage means in the charged condition, means for releasing saidlatching means to permit said energy storage means to open said circuitbreaker, a supplemental opening means comprising a gunpowder mechanismincluding a movable breech, a cartridge arranged to be positioned insaid breech, a firing pin for said cartridge, a plunger positioned so asto be actuated upon firing of said cartridge, means responsive to anabnormal current condition on the circuit associated with said circuitbreaker for actuating said firing pin, and means responsive to movementof said plunger for positively releasing said latching means at highspeed and moving said circuit breaker to the open position.

RALPH R. BUSH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,270,353 Spurck Jan. 20, 19422,319,645 Thumim May 18, 1943

